Many types of electrical connectors have been proposed and used for establishing electrical contact between a wire end and a terminal to which it is connected. So-called "solder lugs" or "crimp lugs" are familiar, to which the wire end is suitably secured and the lug affixed to a terminal by a headed screw which extends through an aperture in the lug. While these devices provide excellent electrical and mechanical connection, they are expensive and require extra labor to apply some to wire ends. To obviate these disadvantages, the wire end is often secured directly to the terminal by a screw, the wire being bent, usually into a partial loop surrounding the screw and disposed between the screw head and terminal. The loop is essential so that the screw head has a bearing about at least 180.degree. of its periphery to prevent eccentric forces on the screw tending to bend it. When it is desired to remove the wire from the screw, the loop must often be straightened or the screw completely removed which, in some cases, is impossible, since the screw may be staked to the terminal to prevent ready removal. Such screw connectors are commonly used in building wiring such as in switches, outlets, and other fixtures. As will be apparent, if the head of the screw could provide a like bearing to prevent eccentric forces thereon and the wire end be left straight, rather than bent into a loop or hook, this would be advantageous, since nothing more than the always necessary paring of the insulation on the wire end would be required. Also, elimination of the loop would reduce installation and removal labor.
When it is desired to connect two wire ends between the screw head and terminal, it is common practice to provide a loop in each wire and stack the loops between the terminal and screw head. In some instances, the screw, which usually is furnished with the electrical fixture, is of insufficient length to permit such stacking, creating a further problem. This is commonly obviated in inexpensive electrical fixtures, such as building outlets and switches, by providing a pair of adjacent screws on a terminal, one for a feeder wire end and the adjacent one for another wire end which joins the next parallel electric fixture. This is only a partial solution, since it is sometimes desirable to connect a third or a fourth wire end to the terminal, again requiring stacking of the wire end loops. It will, thus, be further apparent that if two wire ends could be attached here with a screw head without stacking, further advantage would be attained.
It has also been the practice to splice wire ends with devices which employ set screws, wire clamps, and the like, which are complicated and expensive and designed only for this purpose. It will be further apparent, accordingly, that if a device could be devised the serve as a terminal connector, as previously referred to, and also serve a second purpose of providing a splicer between wire ends, further advantage would be attained by elimination of a single purpose device.
The prior art screw and threaded terminal type connector above referred to, to which the present invention probably most closely appertains, is thus somewhat lacking in optimum utility in that the wire end must be curled or looped to provide a satisfactory connection, requiring additional operations for assembly or disassembly. It also has a single purpose, since it is part of a fixture, such as a plug outlet switch, etc., which are too cumbersome for use as a splicer. As will subsequently appear in more detail, this art is advanced by the provision of a clamping device which may be employed with the former screw, serve a like purpose in an improved manner, and also serve as a wire splicer with the use of a simple screw and nut when desired, further adding to its versatility.